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Electrochemical reforming

Wail Al Zoubi, Muhammad Prisla Kamil, Hae Woong Yang, Young Gun Ko
The electrochemical roles of electron-donor and -acceptor agents in surface reforming of magnesium alloy were investigated via plasma electrolysis. The surface modification was performed in an aluminate-based electrolyte, having urea and hydrazine with inherent molecular structures, which might act as electron acceptor and donor during plasma-assisted electrochemical reaction. The presence of hydrazine working as donor would promote the formation of magnesium aluminates in the oxide layer, resulting in superior compactness of the oxide layer to that when urea was used as the working as acceptor since the precipitation of MgCO3 was favored in the electrolyte with urea...
August 15, 2017: ACS Applied Materials & Interfaces
Eva-Maria Köck, Michaela Kogler, Chen Zhuo, Lukas Schlicker, Maged F Bekheet, Andrew Doran, Aleksander Gurlo, Simon Penner
To account for the explanation of an eventual sensing and catalytic behavior of rhombohedral In2O3 (rh-In2O3) and the dependence of the metastability of the latter on gas atmospheres, in situ electrochemical impedance spectroscopic (EIS), Fourier-transform infrared spectroscopic (FT-IR), in situ X-ray diffraction and in situ thermogravimetric analyses in inert (helium) and reactive gases (hydrogen, carbon monoxide and carbon dioxide) have been conducted to link the gas-dependent electrical conductivity features and the surface chemical properties to its metastability towards cubic In2O3...
July 26, 2017: Physical Chemistry Chemical Physics: PCCP
Wanwan Li, Han Lu, Ning Zhang, Mingming Ma
We report that a postsynthesis physical process (freeze-thaw cycles) can reform the microstructure of conductive polymer hydrogels from clustered nanoparticles to interconnected nanosheets, leading to enhanced mechanical and electrochemical properties. The polyaniline-poly(vinyl alcohol) hydrogel after five freeze-thaw cycles (PPH-5) showed remarkable tensile strength (16.3 MPa), large elongation at break (407%), and high electrochemical capacitance (1053 F·g(-1)). The flexible supercapacitor based on PPH-5 provided a large capacitance (420 mF·cm(-2) and 210 F·g(-1)) and high energy density (18...
June 5, 2017: ACS Applied Materials & Interfaces
Chia-Yu Lin, Yu-Chien Chueh, Cheng-Hsien Wu
An nanoporous nickel oxyhydroxide-borate (NiBi) thin film, consisting of an aggregate of spherical particles self-assembled from NiBi nanopetals, has been synthesized using a simple and cost-effective pulse electrodeposition method without the addition of any surfactant, and demonstrated as an efficient, selective, and robust electrocatalyst in the electrochemical and photoelectrochemical reforming of methanol into formate.
June 29, 2017: Chemical Communications: Chem Comm
Fanglin Che, Su Ha, Jean-Sabin McEwen
The role of low concentrations of carbon complexes in hydrocarbon decomposition over transition metal surfaces has been a topic of much debate over the past decades. It is also a mystery as to whether or not electric fields can enhance hydrocarbon conversion in an electrochemical device at lower than normal reforming temperatures. To provide a "bottom-up" fundamental insight, C-H bond cleavage in methane over Ni-based catalysts was investigated. Our theoretical results show that the presence of carbon or carbide-like species at the interface between the Ni cluster and its metal-oxide support, as well as the application of an external positive electric field, can significantly increase the Ni oxidation state...
February 27, 2017: Angewandte Chemie
Xiaojing Zhao, Lei Dai, Qing Qin, Fei Pei, Chengyi Hu, Nanfeng Zheng
3D PdCu alloy nanosheets exhibit enhanced electrocatalytic activity toward hydrogen evolution reaction and ethanol oxidation reaction in alkaline media. Simultaneous hydrogen and acetate production via a solar-powered cell for ethanol reforming has been fabricated using the nanosheets as bifunctional electrocatalysts. The device is promising for the production of both hydrogen and value-added chemicals using renewable energy.
January 16, 2017: Small
Sen Liu, Xiaolong Zhao, Qingjiang Li, Nan Li, Wei Wang, Qi Liu, Hui Xu
Metal oxide-based electrochemical metallization memory (ECM) shows promising performance for next generation non-volatile memory. The negative-SET behavior has been observed in various oxide-based ECM devices. But the underlying mechanism of this behavior remains unaddressed and the role of the metal cation and oxygen vacancy in this behavior is unclear. In this work, we have observed two kinds of negative-SET (labeled as N-SET1 and N-SET2) behaviors in our Cu/ZrO2/Pt devices. Both the two behaviors can result in hard breakdown due to the high compliance current in reset process...
December 2016: Nanoscale Research Letters
Michael Kitching, Robin Butler, Enrico Marsili
Sustainable energy supplies are needed to supplement and eventually replace fossil fuels. Molecular hydrogen H2 is a clean burning, high-energy fuel that is also used as reducing gas in industrial processes. H2 is mainly synthesized by steam reforming of natural gas, a non-renewable fuel. There are biosynthetic strategies for H2 production; however, they are associated with poor yield and have high cost. The application of an electrochemical driving force in a microbial electrolysis cell (MEC) improves the yield of biological reactions...
January 2017: Enzyme and Microbial Technology
Kai Li, Lichao Jia, Xin Wang, Jian Pu, Bo Chi, Jian Li
Ni0.9Fe0.1 alloy-supported solid oxide fuel cells with NiTiO3 (NTO) infiltrated into the cell support from 0 to 4 wt.% are prepared and investigated for CH4 steam reforming activity and electrochemical performance. The infiltrated NiTiO3 is reduced to TiO2-supported Ni particles in H2 at 650 °C. The reforming activity of the Ni0.9Fe0.1-support is increased by the presence of the TiO2-supported Ni particles; 3 wt.% is the optimal value of the added NTO, corresponding to the highest reforming activity, resistance to carbon deposition and electrochemical performance of the cell...
October 24, 2016: Scientific Reports
Ryan J Milcarek, Michael J Garrett, Amrish Baskaran, Jeongmin Ahn
Combustion based power generation has been accomplished for many years through a number of heat engine systems. Recently, a move towards small scale power generation and micro combustion as well as development in fuel cell research has created new means of power generation that combine solid oxide fuel cells with open flames and combustion exhaust. Instead of relying upon the heat of combustion, these solid oxide fuel cell systems rely on reforming of the fuel via combustion to generate syngas for electrochemical power generation...
October 2, 2016: Journal of Visualized Experiments: JoVE
Christopher Batchelor-McAuley, Christopher A Little, Stanislav V Sokolov, Enno Kätelhön, Giorgia Zampardi, Richard G Compton
The lipid soluble fluorophore Nile Red (9-diethylamino-5-benzo[α]phenoxazinone) is used to fluorescently and electrochemically label an organic-in-water emulsion, where the organic phase is an ionic liquid [P6,6,6,14][FAP]/toluene mixture. The optical detection of the individual droplets is enabled facilitating the in situ tracking and sizing of the suspended particles (average diameter = 530 nm, interquartile range = 180 nm). Through the use of a combined thin-layer optical/electrochemical cell, the irreversible accumulation of the droplets at an optically opaque carbon fiber electrode (diameter ∼7...
November 15, 2016: Analytical Chemistry
Dan Xu, Ranran Jiao, Yuanwei Sun, Dezhi Sun, Xianxi Zhang, Suyuan Zeng, Youying Di
MnS has been attracting more and more attentions in the fields of lithium ion batteries (LIBs) because of its high energy density and low voltage potential. In this paper, we present a simple method for the preparation of urchin-like γ-MnS microstructures using L-cysteine and MnCl2 · 4H2O as the starting materials. The urchin-like γ-MnS microstructures exhibit excellent cycling stability (823.4 mA h g(-1) at a current density of 500 mA g(-1), after 1000 cycles). And the discharge voltage is about 0...
December 2016: Nanoscale Research Letters
Kai Leng, Zhongxin Chen, Xiaoxu Zhao, Wei Tang, Bingbing Tian, Chang Tai Nai, Wu Zhou, Kian Ping Loh
Achieving homogeneous phase transition and uniform charge distribution is essential for good cycle stability and high capacity when phase conversion materials are used as electrodes. Herein, we show that chemical lithiation of bulk 2H-MoS2 distorts its crystalline domains in three primary directions to produce mosaic-like 1T' nanocrystalline domains, which improve phase and charge uniformity during subsequent electrochemical phase conversion. 1T'-LixMoS2, a macroscopic dense material with interconnected nanoscale grains, show unprecedented cycle stability and rate capability in lithium rechargeable battery compared to bulk or exfoliated-restacked MoS2...
September 16, 2016: ACS Nano
Lei Dai, Qing Qin, Xiaojing Zhao, Chaofa Xu, Chengyi Hu, Shiguang Mo, Yu Olivia Wang, Shuichao Lin, Zichao Tang, Nanfeng Zheng
Electrochemical partial reforming of organics provides an alternative strategy to produce valuable organic compounds while generating H2 under mild conditions. In this work, highly selective electrochemical reforming of ethanol into ethyl acetate is successfully achieved by using ultrathin Co3O4 nanosheets with exposed (111) facets as an anode catalyst. Those nanosheets were synthesized by a one-pot, templateless hydrothermal method with the use of ammonia. NH3 was demonstrated critical to the overall formation of ultrathin Co3O4 nanosheets...
August 24, 2016: ACS Central Science
K Tseronis, I S Fragkopoulos, I Bonis, C Theodoropoulos
Fuel flexibility is a significant advantage of solid oxide fuel cells (SOFCs) and can be attributed to their high operating temperature. Here we consider a direct internal reforming solid oxide fuel cell setup in which a separate fuel reformer is not required. We construct a multidimensional, detailed model of a planar solid oxide fuel cell, where mass transport in the fuel channel is modeled using the Stefan-Maxwell model, whereas the mass transport within the porous electrodes is simulated using the Dusty-Gas model...
June 2016: Fuel Cells (Weinheim)
Peng Zhang, Jingjing Tong, Youngseok Jee, Kevin Huang
A high-selectivity and high-flux electrochemical silver-carbonate dual-phase membrane was coated with a nanoscaled ZrO2 layer by atomic layer deposition (ALD) for stable CO2 capture at high-temperature (≥800 °C); the latter has an important implication for direct dry methane reforming with the captured CO2 and O2 for syngas production.
July 28, 2016: Chemical Communications: Chem Comm
Sandra Jenatsch, Lei Wang, Matia Bulloni, Anna C Véron, Beat Ruhstaller, Stéphane Altazin, Frank Nüesch, Roland Hany
Cyanine dyes are fluorescent organic salts with intrinsic conductivity for ionic and electronic charges. Recently ( J. Am. Chem. Soc. 2013 , 135 , 18008 - 18011 ), these features have been exploited in cyanine light-emitting electrochemical cells (LECs). Here, we demonstrate that stacked, constant-voltage driven trimethine cyanine LECs with various counteranions develop a p-i-n junction that is composed of p- and n-doped zones and an intrinsic region where light-emission occurs. We introduce a method that combines spectral photocurrent response measurements with optical modeling and find that at maximum current the intrinsic region is centered at ∼37% away from the anode...
March 2016: ACS Applied Materials & Interfaces
Hella Logtenberg, Jetsuda Areephong, Jurica Bauer, Auke Meetsma, Ben L Feringa, Wesley R Browne
Redox-driven molecular motion is an attractive alternative to light-driven processes. Here, the ability of an overcrowded alkene-based unimolecular light-driven rotary motor (A) to be driven by oxidation/reduction cycles is explored. We show that two-electron oxidation of A is followed by irreversible deprotonation and reduction to form a monocationic species D(+) , in which the stereogenic center is lost. This latter species was isolated through preparative electrolysis and its structure was confirmed by using single-crystal X-ray analysis...
June 17, 2016: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Phoebe K Allan, John M Griffin, Ali Darwiche, Olaf J Borkiewicz, Kamila M Wiaderek, Karena W Chapman, Andrew J Morris, Peter J Chupas, Laure Monconduit, Clare P Grey
Operando pair distribution function (PDF) analysis and ex situ (23)Na magic-angle spinning solid-state nuclear magnetic resonance (MAS ssNMR) spectroscopy are used to gain insight into the alloying mechanism of high-capacity antimony anodes for sodium-ion batteries. Subtraction of the PDF of crystalline NaxSb phases from the total PDF, an approach constrained by chemical phase information gained from (23)Na ssNMR in reference to relevant model compounds, identifies two previously uncharacterized intermediate species formed electrochemically; a-Na(3-x)Sb (x ≈ 0...
February 24, 2016: Journal of the American Chemical Society
Siham Doubaji, Bertrand Philippe, Ismael Saadoune, Mihaela Gorgoi, Torbjorn Gustafsson, Abderrahim Solhy, Mario Valvo, Håkan Rensmo, Kristina Edström
The cathode material P2-Nax Co2/3 Mn2/9 Ni1/9 O2, which could be used in Na-ion batteries, was investigated through synchrotron-based hard X-ray photoelectron spectroscopy (HAXPES). Nondestructive analysis was made through the electrode/electrolyte interface of the first electrochemical cycle to ensure access to information not only on the active material, but also on the passivation layer formed at the electrode surface and referred to as the solid permeable interface (SPI). This investigation clearly shows the role of the SPI and the complexity of the redox reactions...
January 8, 2016: ChemSusChem
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